Monthly Archives: July 2011

Rail and switch review

I found a picture that I’d taken a while ago of switches near Rose Quarter- it probably should have gone in my last post but I’ll put it here and make this a review post about switches and rail types. First: rail types.

Borrowed picture which shows cross-sections of both types of rail used on the MAX alignment: t-rail on the left, girder rail on the right. Girder rail is used in lower speed areas (CBD/downtown & Holladay, Washington Street in Hillsboro), and t-rail is used everywhere else. Along Interstate, the t-rail is embedded in pavement so it looks similar to girder rail. This picture shows the embedded rail on Interstate along with the crossover switches that are not embedded.

Here is the picture of Rose Quarter, where girder rail is what’s used:

Switches, looking east from the westbound platform at Rose Quarter

This picture shows the different routing options available on the eastern side of the Rose Quarter platform. The nearest track is the westbound mainline, the one diverging off to the left side of the picture leads to the trolley barn, the one that’s actually a straight route from the westbound mainline is the special events track, and the far track is the eastbound mainline. In this type of rail, the only way to tell how switches are set is by observing the switch points – while the ABS/combination signals associated with these switches tell you what the route is, it’s still necessary to observe that the switches are set properly.

West Ladder, Elmonica Yard

Compare the switches at Rose Quarter to these in the Elmo yard, facing the storage tracks. These t-rail switches are power switches, meaning they can be thrown remotely from the cab of a train, and they have switch indicators (green for switches set normal, yellow for switches set diverging – remember manual switches in t-rail use targets with the same colors). You can see how the color of the indicator matches how the switch points are aligned. Girder rail switches don’t have indicators like these to make it easier to tell how the switch points are set, but even with indicators it’s still always necessary to observe switch points – an indicator can be wrong, but switch points never are.

Rose Quarter

For reader Matt, who had asked about signals at Rose Quarter some 6 months ago and I’m finally writing about it. In other words, it’s a good thing “Professional Blogger / Fielder of Questions” isn’t what TriMet hired me to do.

The Rose Quarter interlocking is very complex (I’ve heard it’s one of the most complex in the country, but I don’t really have much of a basis for comparison). I’d wager it’s probably also one of the busiest, with trains passing through every few minutes. The complexity of this interlocking’s design allows for a lot of flexibility for trains in the event of a bridge lift or other reroutes.

For simplicity, in this post RQ refers to the Rose Quarter platform used by Blue, Red, and Green Line trains. IRQ refers to the Interstate Rose Quarter platform used by Yellow Line trains.

First, the whole thing from above:

As always, click for larger

Rose Quarter Platform

Starting with the signals associated with the Rose Quarter platform.

Looking west into RQ from OCC

Coming into Rose Quarter from the east (Oregon Convention Center platform), the first signals you encounter are 18A and 18B. 18A protects switches 13A, 11C, and 11D, and will remain red with an active ATS magnet if any of those switches are not aligned to move west or if there is a conflicting move in progress (e.g. a vintage trolley coming in or out of the trolley barn). 18B gives you a choice of routes between the special events track which is the middle platform, the westbound mainline track which is located to the right of the special events track, or the trolley barn.

Now in the RQ platform, looking westbound first:

16B and 16C can display identical aspects for identical routes (remember, it’s not where you are, it’s where you’re going) – the only difference is that 16B is for trains heading west from the special events track and 16C is for trains in the westbound main. A white vertical will send you toward the Steel Bridge; a red over white vertical will send you toward IRQ (Yellow Line). These signals will stay red if the bridge span is unlocked for a lift, or if there is a conflicting move in progress with the Yellow Line.

And then east from Rose Quarter:

18D, which is used by vintage trolleys leaving the barn – a white vertical to continue to the eastbound mainline; a red over white vertical for a reverse move onto the westbound mainline.

18E and 18F (similar to 16B and 16C) can display identical aspects for identical routes, with 18E used by trains in the westbound main and 18F used by trains in the special events track. A white vertical will send trains east on the eastbound mainline; a red over white vertical will send trains east on the westbound mainline.

18G is the signal for eastbound trains in the eastbound mainline at RQ – no choice of routes available here. Memory trick for memorizing signal numbers (though I don’t think they do that anymore in rail training) – “G” for Gresham, and signal 18G will get you there.

Then away from the Rose Quarter platform itself…

Interstate Rose Quarter Platform

16E at the IRQ platform. A white vertical on 16E will send Yellow Line trains over the Steel Bridge; a red over white vertical will send them into Rose Quarter. This is how Yellow Line trains can get from Expo to the Ruby yard at the end of the day. Also, when a Yellow Line train operator forgets to change the route code in their trailing cab from Clackamas’s 12 to Jackson’s 50, they get a red over white vertical here.

Then at the other end of IRQ are N2A (for trains heading north from the southbound track) and N2B (for trains heading north from the northbound track) – like Rose Quarter, IRQ is also set up to allow turnbacks in the event of a bridge lift. A lunar on these signals will send trains on the northbound mainline; a red over lunar into the Broadway Siding – you may have been on a train in the morning where it stops at IRQ, kicks everyone off, but then appears to continue north. It only goes as far as the Broadway Siding before turning around and going back west over the Steel Bridge. (Linked video was not filmed, narrated, or posted by me and does not feature me. Linked video is also old, Train 6 hasn’t done that for a while, but 33 does it currently)

Coming off the Steel Bridge

16G will display a lunar for trains heading into RQ (Blue, Red, and Green Line trains), and a red over lunar for trains heading into IRQ (Yellow Line trains).

Assorted pics of and through the interlocking

Both heading westbound toward the Steel Bridge from Rose Quarter

Can diverge to or from IRQ

You can see how you can get from either track at IRQ to RQ or the Steel Bridge

Switches and crossovers

I also have this video which I’d originally posted a few months ago, showing a view from the cab from 1st and Morrison to Rose Quarter. This was a Red Line train, so we got a lunar on 16G and went through the interlocking at the same time as another Red Line Train.

Making a parallel move with a westbound train

Given the design of Rose Quarter, what’s ideal for train movement are parallel moves, where trains can move in opposite directions at the same time. Scheduling trains to do this reduces the need to wait for other trains (e.g. sitting at RQ waiting because a Yellow Line is going through, so the switches are set against you) as well as reducing the impact that trains moving through the intersection has on auto/bike/pedestrian traffic.

Yellow Line trains making a parallel move

Train numbers, route codes, and more with signals

Question: How does a train know where to go?

This question comes up a lot, and although I’ve answered it in comments or emails or Twitter, I’ve never given it its own post. But a lot of people have asked, for example, if a train is eastbound at Gateway, what do you do to it to send it to Gresham vs the airport vs Clackamas? Sure you call the signal but how do you get the right aspect(s) to come up for where you want to go? It’s not like the trains have a steering wheel.

(Actually it’s kind of fun to let kids see the cab of a train at the end of the line and ask them where the steering wheel is. It stumps their parents too!)

It’s a trick question.  Here’s the “steering wheel” of a MAX train:

Route code (and train number, which is blurred out, you don’t need to know what train number this was, but in following safety procedures, I assure you the train was stopped at the end of the line – not only was it not moving it wasn’t even keyed in), Type 2 thumbwheels

In the cab of each train is a place to set the train number (under normal operating conditions, this won’t change over the course of the day) and also the route code. The train number is the train’s identifier, and it matches the number visible in the window box – for example, the train in the old header picture of this blog was train 40; the train in the old background image was 71. If Control wants you, they’ll call your train number over the radio. If you need something, you begin a radio call to Control by stating your train number.

You can tell what yard a train is from (though not necessarily what yard the operator is from due to reliefs) and what color its route is from the train number. Trains 1-15 are Blue originating out of Ruby, 20-38 are Blue out of Elmonica, 40-53 are Red out of Elmonica, 60-74 are Yellow/Green out of Ruby, and the Mall Shuttle had been train 89 out of Ruby. Trains not regularly scheduled, such as those used for testing or burn-in get numbers in the 90s. There are some exceptions to this breakdown, like train 10 is Blue most of the day but becomes Red at night, 43 begins its day going from Elmo to PDX to Hatfield before becoming a regular Red Line, but this is all pretty much just trivia for passengers anyway, it’s not like I’m going to quiz you on this later.

The route code is what tells the train where to go from its current location. Every possible destination on the alignment that can be reached via power switches has a route code assigned to it – not just the ends of each line, but also the yards, sidings, pocket tracks, etc.

Sign at Galleria with 11th Ave route code

In the first picture in this post, a route code of 50 will get a train to either track 1 or 3 in the Jackson turnaround by PSU, whichever is open. Every time an operator places a train-to-wayside call over a call loop, the switches will be set to move the train toward the destination set as the route code, and the corresponding signals will be displayed. Operators are responsible for ensuring the route code is correct for where the train is supposed to go. For Blue and Red line trains, this is pretty easy – the cab that leads going east will be set for Gresham or PDX, and the cab that leads west will be set for Hillsboro or BTC so it does not need to be adjusted frequently (well, it’s easy as long as Red line operators don’t forget to change the route code from the BTC pocket track on the last trip and end up in there when they need to keep going west…).

Yellow/Green line trains are a little trickier. For trains leaving Ruby to service those lines, depending on which run it is the route code will be set for Expo, the Jackson turnaround, or the Gateway auxiliary track (where the operator will swap cabs and take the train to Clackamas). Then to change color at Jackson, the operator will leave Clackamas (for example) with the route code for the Jackson turnaround, and then once there will set the route code for Expo. When leaving Expo in the other cab, they’ll set the route code for Jackson, and then once in the Jackson turnaround, they’ll change the route code for Clackamas. Potential errors can happen if an operator forgets to change the route code from 50 when leaving Jackson (if that happens, the train will head back south to PSU from Union Station instead of crossing the Steel Bridge) or forgetting to set the route code for Jackson from the end of the line (so for example, heading toward Clackamas from Interstate Rose Quarter instead of over the Steel Bridge).

Signal aspect review

Signals will reflect what route code is in your thumbwheel. First, here’s a quick overview  of signal aspects (for more information, I’ve written a lot about signals already)

A red aspect – STOP

A yellow aspect – clear for one ABS block (that is, the distance to the next ABS signal) on the primary route

A green aspect – clear for two ABS blocks on the primary route

A lunar aspect – proceed with caution, tracks may not be clear (your switches are set but no indication of train occupancy ahead)

The number of aspects that are lit indicates which route you’ll be going on (one aspect = primary route, or “A” route. Two aspects = secondary route or “B” route. Three aspects = tertiary “C” route, etc). As an operator, when you’re looking at a signal that can display more than one route, you need to know which of those routes corresponds with the route code you have in your thumbwheel.

Back when I was first learning the signals, one of the most confusing parts for me was confounding signal aspects with switch positions, in part because yellow over green signals are referred to as “advanced diverging” and red over yellow are referred to as “diverging” – so that means when you see one of those signals, you can expect switches to be set diverging, right? Well, not necessarily…

For example, at the ends of the lines (here into Cleveland Ave from Gresham TC) a single yellow aspect will actually put you over diverging switches into Cleveland, but a red over yellow is a straight shot in. A signal with two aspects means that you’re diverging from the primary route, but not necessarily diverging over switches – it could be that the primary route itself diverges over switches but the secondary route goes straight. I had been thinking about the ABS signals in terms of switches, not routes, and that was a stumbling block for me. A permissive signal indicates that your switches are set for whatever your route code is, but you have to know if that means they’re diverging or normal.

Same with this red over white vertical on W1760 at Hatfield – it’s a secondary route (2 aspects), but this train will be going straight in, not diverging over the switches. Sorry for the blurry picture but it’s the only one I have.. I either need to go out there and get a clearer one or get someone to do that for me.

It’s not where you are, it’s where you’re going

So keeping in mind that an ABS (or ABS-pre-empt combination) signal displays your route, here’s an example of what it looks like when you can call the same route from two different locations. Take a look at these signals:

Signal 76: Red over red over green
Clear for 2 ABS blocks to Clackamas TC

Signal 78: Red over red over yellow
Clear for 1 ABS block to Clackamas TC

Both trains that called these are facing east at Gateway – the one looking at signal 76 is in the eastbound main; the one looking at signal 78 is in the pocket track. Both have a route code set for Clackamas TC. And from both tracks, that’s the “C” route / 3rd route / tertiary route, which is why both signals are showing 3 aspects. These aspects are almost functionally identical (the yellow on 78 just means that this train’s leader is only one ABS block ahead of them, otherwise that would’ve been a green) even though the train observing signal 78 has two more sets of switches to diverge over to get to the eastbound main to get to Clackamas.

Gateway from above, click for larger

The platforms are in the bottom of the picture – from left to right, that’s the westbound mainline, pocket track, and eastbound mainline. Notice that to get over to the eastbound main alignment (which, out of range of the top of the picture, diverges off to Clackamas) a train in the pocket track has to pass over the switches that could otherwise bring it to the auxiliary track, and then over another set of switches to join the eastbound main. Yet its signal aspect at Gateway to get to Clackamas is identical to what a train in the eastbound mainline would get, even though the train in the eastbound mainline doesn’t have to worry about those switches.

Where a train is starting from doesn’t matter – where it’s heading is what will be displayed on the signal.

Lunar on signal 78, eastbound from Gateway pocket track

Lunar on signal 76, eastbound main at Gateway

Similarly, a train with a route code for Cleveland (or the Ruby Yard) going east from the pocket track will get a single lunar aspect on signal 78, just like how a Blue Line train heading east at Gateway will have a lunar on signal 76, even though a train starting from the pocket track has to diverge over switches to get there. The signal indicates that the switches are set for the route code in  your thumbwheel, but you have to know if that means the switches are set normal or diverging (because you do NOT take a train at a high speed over these diverging switches!)

Here’s another example, eastbound at Beaverton Transit Center.

Signal W760 is for a train in the pocket track (which is typically a Red Line), and W754 is the signal for the eastbound main. A train heading east from the pocket track will have to diverge over switches to get into the eastbound main, yet the ABS signal will show a single aspect indicating the primary “A” route. It doesn’t matter where the train is at, it matters where it’s going – and for trains in either track here, the only place to go is the eastbound main (primary route), therefore both signals have a single head that can only display a single aspect. There is no choice of route from either track, even though you will be diverging into the main eastbound track if you are leaving the pocket track.

W556 at Sunset, for a Red Line train heading to the BTC pocket track

On the other hand, if you’re headed west into BTC, you do have a choice of two routes (along the westbound mainline or into the pocket track), which is why signal W556 at Sunset and the intermediate signals leading into BTC (W616 and W716) can all display one or two aspects for a primary or secondary route. The signals will indicate that the switches are set for whichever of those route codes you have in your thumbwheel.

You know, I don’t know how to end posts. I feel like I should assign a 2-page essay on the importance of ensuring you have the right route code in your thumbwheel and how that relates to ABS signal aspects. Show your work.

Call board safety video

From the “I forgot I had this” files (sometimes I have the memory of a goldfish). This is a short TriMet safety video about call boards and their use to protect workers in the right of way. Safety at rail is not a joke and it’s never taken lightly because of how severe the consequences of a lapse in safety can be. I think it’s a good thing for the public to see things like this because ordinarily they don’t get the opportunity to watch how much effort goes on “behind the scenes” to keep things running smoothly and safely.